FWIW: Oil Pressure Gauge Issues

[pinstriper38]

Just wanted to post an "interesting" issue I had recently with my oil pressure gauge.

About a month ago, I went out to the garage and noticed a large coolant puddle underneath the car. "Great." I thought. "Now my water pump has gone to crap." I said to myself. Nope. Further inspection revealed that it was seeping coolant from the timing chain cover gasket, which was even awesome-r! Long story short, got that all resolved and a new water pump to boot and everything was good... for about a week.

Then one day I was heading to a movie with the ladyfriend and all of a sudden the car goes into full-on freakout mode, and my oil pressure gauge is dancing around like mad. "Awww *insert expletive here*, now how did I mess this up??". I've never seen a gauge act this way but it was all over the place. Back and forth from 0 to 40 to 60 to nothing again and that incessant chime every 5 seconds telling me that my engine was sure to implode. After checking the oil and listening for any weird noises, I decided that the car should be ok to drive, because I've never seen oil pressure swing that wildly. After messing with the wires and swapping out another oil pressure sending unit with yet another bad one from the junkyard (just pegged the gauge at 120) I finally broke down and coughed up the money for a new sending unit (nothing like doing a job 3/4/5 times because you're cheap, right?) and for the last month all has been well.

I guess that when the unit goes bad, it can just peg the gauge or it can make it do crazy things, like mine did.

[RJolly87]

When the unit failed in my dad's 97 Ultra, it was flipping from 0 to Max intermittently. The typical failure is pegging the gauge to the max, but as you discovered, they don't all fail that way.

[MKMike]

Very interesting.
Didn't know they sometimes fail that way.
Thanks for sharing the info.